Read and decompile a Java .class file from a JAR to inspect game code for modding. Use it to analyze classes before patching Java-based games.
Read and decompile a Java .class file.
| Name | Required | Description | Default |
|---|---|---|---|
| decompile | No | Decompile to Java source (default: true) | |
| class_path | Yes | Path to .class file within JAR | |
| session_id | Yes | Session ID | |
| extra_classpath | No | Additional classpath entries |
Changes observed during successful MCP inspections.
v0.1.4Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full behavioral burden. It states read/decompile but discloses nothing about the required session state, whether the class must already exist in an open JAR, error behavior, or what the decompile default (already in schema) actually yields.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
A single front-loaded sentence with no wasted words. It is efficient, though arguably too terse to be maximally useful.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a stateful tool requiring a session_id plus a class path, with no annotations and no output schema, the description is too thin. It omits session context, the relationship to jar_open/jar_list, and any notion of what decompilation returns.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100%, so the schema already documents all four parameters including the decompile default. The description adds no syntax or format meaning beyond the schema, which is the expected baseline of 3 when the schema does the heavy lifting.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
States a specific verb ('read and decompile') and resource (Java .class file), so an agent knows exactly what it operates on. However, it does not distinguish itself from siblings like decompile_type, decompile_method, or inspect_type, leaving the agent to guess which class-level vs type-level tool applies.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description gives no when-to-use context, no prerequisites (e.g. an open JAR session), and no routing guidance relative to the many decompile/inspect siblings. Usage is only implied by the name.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.